In the past, sensors have been used in a variety of applications including, but not limited to, sensing moisture, humidity, sound, temperature, light, gases, chemicals, magnetic fields, electrical currents, voltages, fluid flow, liquid volume, concentrations of solutes in liquids, tire pressure, biological materials in a liquid sample, and physical stresses. Most sensors are discrete elements designed to sense a particular parameter. A discrete sensor is mounted to a rigid structure such as a printed circuit. Depending on the application, other devices such as, for example, discrete switches, control devices, and heat removal structures, may be mounted on the rigid structure along with the discrete sensor. The heat removal structures may be cooling fins that are coupled to the power devices, wherein the heat removal structures are mounted to a separate structure from the structure on which the power device is mounted. Because of the number of discrete components used to make up an electronic system is large, these systems tend to be bulky, heavy, and expensive to manufacture.
By way of example, a pressure sensor is typically a discrete sensor that is mounted to a printed circuit board. The pressure sensor may be made up of a thin layer of stainless steel that has two strain gauges attached along two of its axes. Pressure is indirectly measured by deforming the thin stainless steel layer where the bending changes the ohmic resistance of the attached strain gauges by less than 0.1 percent. The change in ohmic resistance is determined using a Wheatstone bridge. The accuracy of the measurement depends on the thickness of the stainless steel layer, the accuracy of the resistors of the Wheatstone bridge, temperature coefficients of the components making up the pressure sensor, etc. If the sensor is configured as an array of sensors, the accuracy of the measurement is also dependent on the distance between the sensors. Drawbacks with pressure sensors mounted to printed circuit boards include their size and the weight of the strain gauges.
Thus, a sensor structure capable of sensing more than a single parameter includes a plurality of sensors. For example, to measure temperature, humidity, and pressure, three discrete sensors are mounted to a rigid structure such as a printed circuit board and electrically connected to sensory electronics that are also mounted to the printed circuit board.
Another class of discrete sensors are bio-sensors. These types of sensors may be used to monitor a component of blood, such as blood glucose. A drawback with these types of sensors is that the analytes, reactants, and by-products in the sensors must be purged and removed before the sensors can be re-used.
Accordingly, it would be advantageous to have sensors or sensor structures capable of providing continuous monitoring, that can monitor one or more parameters, that are light weight, and portable, and that can be purged and reused. It would be of further advantage for the semiconductor components, sensing elements, electronics, sensors, power devices, etc. and the methods of sensing and manufacturing of the sensors to be cost and time efficient to implement.
For simplicity and clarity of illustration, elements in the figures are not necessarily to scale, and the same reference characters in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action and the initial action. The use of the words approximately, about, or substantially means that a value of an element has a parameter that is expected to be very close to a stated value or position. However, as is well known in the art there are always minor variances that prevent the values or positions from being exactly as stated. It is well established in the art that variances of up to about ten per cent (10%) (and up to twenty per cent (20%) for semiconductor doping concentrations) are regarded as reasonable variances from the ideal goal of being exactly as described.